Oil black after one ride!

I 've been working out the bugs with this '04 YZ450F and I now have it running correctly after replacing the carb, setting the valves corretly,installing the correct hot mechanism and fixing a grounded neutral switch but after I took it out for it's 1st ride ( I had previously changed the oil since I had to replace the water pump seals) and then changed the oil for the 2nd time, it was blacker than I remember seeing any of my other YZ thumpers. I also had installed a new oil filter and it had alot of crap in it; it wasn't packed but more than I would expect from only 1 ride. We rode the bike for about 1.5 hours on a tight MX track. The bike does have some time on it; it was raced/ridden by a pro off road

guy so I am thinking that maybe the cam chain guides are toast among other things?

Any ideas as to why the oil would be black after only 1.5 hrs of riding?

The first thing that comes to mind is that your previous oil change interval was too long, and the new oil picked up the black color as it was cleaning up the interior of your engine. Oil should be changed after around ten hours, IMO. Filter too.

Another source of black junk is your clutch. Do you slip it a lot?

No, I don't slip the clutch much but I may have used a few times but it looked like I had ridden it 5 or 6 times. So, I guess maybe this caused it but I don't remember any of my 250F's, 426's or 400's looking like this. I do remember my son's 250F looking black like this after 5 hard rides, he forgot to change after 3 (he puts alot of time on his bikes).

thx for th reply!

Just change the oil a few times, and it should start to clean up. I wouldn't be concerend about black oil, that only means the oil changes are not being done enough. Now, if you start finding abnormal amounts of metal or something in the filter, then I would start worring.

i had that happen to me on a weekend at pismo beach. went from fresh oil to black in one ride. in this instance it turned out to be my clutch. i dont use it much either but those beasts have a bit o torque goin on and stock aluminum plates after a season of use will go any way (and a couple real hard trips in the dunes dont help). and a miss management of clutch adjustment (my fault, hopefully learned from it). put aftermarket steel plated clutch and all good. through another season and got hardly any noticable wear happinin. and clean oil. :)

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